This invention relates to vitamin D compounds. More specifically the invention relates to a new synthesis of 1.alpha.,24(R)-and 1.alpha.,24(S)-dihydroxy-22(E)-dehydrovitamin D.sub.3, and to novel vitamin D derivatives generated as intermediates in the synthetic process.
The 24(R)- and 24(S)-epimers of 1.alpha.,24-dihydroxy-22-dehydrovitamin D.sub.3 are known compounds, their preparation being disclosed in U.S. Pat. No. 4,588,528. This known preparation is, however, a lengthy multi-step process, which entails, moreover, a difficult separation of stereoisomers at an early stage of the synthesis. Since the compounds possess, however, high biological activity, which renders them useful as potential therapeutic agents for the treatment of calcium metabolism-related disorders, such as renal osteodystrophy, hyperparathyroidism, osteoporosis, or of skin disorders such as psoriasis, the development of a new synthetic process, which would provide for the more efficient and convenient preparation of these compounds becomes an important objective.